摘 要 ：本文报道了开口箭属（Tupistra）的2个新分类群，并对开口箭属内形态特征演化趋势进行了探讨，认为：l花柱较短，柱头较小，花药高于或等高于柱头的种比较原始；花柱较长而柱头肉质膨大，花药低于柱头的种相对进化；2.每花具单枚苞片的种比每花具多枚苞片的种原始；3.花被简内无环状附属体进化到花被简内具环状体；4.核型由对称性较强进化到对称性较弱，进而演化成二型性核型。据此，开口箭属可划分为2个亚属5个组，系统顺序如下：1.短柱亚属Subegnus Campylandra（Baker）H.Li et J．L．Huang：1.弯蕊组 Sect．Campylandra（Baker）Franch．；2.环状花组Sect.Annulatae H.Li et J.L.Huang；Ⅱ.开日箭亚属 Subgenus Tupistra：4.垂花组 Sect．Nutantes H.Li et J.L.Huang；5．开口箭组Sect．Tupistra.
Abstract:In this paper, 2 new taxa of the genus Tupistra Ker-Gawl. are reported and 4 viewpoints about the evolutionary trend within the genus are submitted as following: 1.Spe-cies with flowers of short styles and small stingmas lower than of as high as anthers is primitive while that of long styles and big stigmas higher than anthers is advanced; 2. Species with flow-ers without annuli in perianth tubes is more primitive than that with annuli; 3.Species with flowers of 1 bract each is more primitive than that of several bracts; 4. Karyotype evolves from symmetry to asymmetry then bimodal.